1. Field of the Invention
The invention relates to handover technique in a mobile wireless communication network. In particular, the invention relates to a mobile wireless communication system, a method of carrying out handover in the system, a wireless station used in the system, a mobile communication terminal device used in the system, a program for causing the wireless station to carry out the method, and a program for causing the mobile communication terminal device to carry out the method.
2. Description of the Related Art
Many attempts have been made with respect to handover between adjacent wireless stations.
For instance, one of examples is disclosed in Japanese Patent Application Publication No. 2005-509327.
It is supposed that a mobile communication terminal device is making wireless communication with a first base station, and is moving in a direction from the first base station towards a second base station disposed adjacent to the first base station. If the mobile communication terminal device detects reduction in a strength of an electric field for receiving signals from the first base station, increase in power for transmitting signals, or increase in a signal-interference ratio (SIR) in the second base station, the mobile communication terminal device treats them as triggers for starting carrying out handover to the second base station from the first base station.